1. Suppose A = -12 B = -7 -3 A C = If possible, give AB. If the product is not defined, then give a reason. b. If possible, give BA. If the product is not defined, then give a reason. C. If possible, give AC. If the product is not defined, then give a reason. . If possible, give CA. If the product is not defined, then give a reason. 2. Given the system 2x1 - 3x2 + 23 = -1 2x1 - 12 + 13 = 7 a. Write this system as a vector equation. b. Write this system as a matrix equation. 3. Let A= 19 -12 Determine which of the following vectors are in the plane spanned by columns of A. Give reasons for your answer. You can use the RREF command on this problem so long as you document your work. b